Electron tube with luminescent shield, especially tuning tube



A ril 22, 1952 w. JACOBI ETAL 2,594,025

ELECTRON TUBE WITH LUMINESCENT SHIELD, ESPECIALLY. TUNING TUBES FiledOct. 3, 1950 IIIIAKK'WIIZ Patented Apr. 22, 1952 ELECTRON TUBE WITHLUMINESCENT SHIELD, ESPECIALLY TUNING TUBE Werner Jacobi, Erlangen, andHermann Hinder-er,

Marloffstein, near Erlangen, Germany, assignors to Siemens & HalskeAktiengesellschaft,

Germany, a corporation Berlin- Siemensstadt,

of Germany Application October 3,1950, Serial No. 188,162

In Germany September 9,1949

This invention is concerned with electron dis charge devices, especiallytuning tubes, having fluorescent" electrodes which are rendered luminousto produce for indicating purposes patterns of light in response toapplied voltages.

The object of the invention is to provide a discharge device of theabove noted type having a fluorescent electrode which comprises an elongated transparent support, e. g, a glass support, carrying a narrowstrip or band of fluorescent substance substantially throughout itslongitu dinal extent. The fluorescent substance is rendered luminousresponsive to applied voltages and produces a narrow, luminousindicating column of different length according to the voltage applied.This luminous indicating column may be viewed through the transparentsupport along lines of observation which lie entirely outside oftheremaining electrode members of the discharge device, .thus permittingobservation.of the entire area of the luminous column and therebyproviding for clear and unobstructed indication; The various elements ofthe new structure are arranged in a manner to save space.

The term transparent is intended to embrace the meaning usually attachedto the'term translucent, or similar language. The term fglass employedherein with reference to the material used for the support of thefluorescent substance, unless otherwise restricted, is intended toinclude glass as such, as well as any other desired and suitablematerial which is transparent or substantially transparent, so as tosatisfy the requirements of the invention.

The fluorescent substance may be provided on the transparent support'inthe form of a thin, striplike layer of such moderate thickness as toprevent charging. The support for the fluorescent substance may beprovided with a suitable conductive substantially transparent coatmg.

The use of a glass rod of cross-sectionally substantially cylindrical orheart shaped configuration was' iound particularly suitable. Such aglass body may be made in the form of a thin rod of a few millimetersthickness. The fluorescent substance may be applied to the glass rod bypowdering or by sedimentation with the use of suitable masks. The glassrod may also be provided with a shallow groove, e. g., by etchins, towhich the luminescent substance adheres while it is wiped off fromthe'remainder of,.the rod. The indication provided by the luminousfluorescent substance on the glass rod may be observed either obliquelyfrom the front or from 8 Claims. (Cl. 313107.5)

in rear, the directions ofviewing which are not obstructed by members ofthe remaining electrode system of the discharge device.

The optical properties of the transparent rod may be utilized by givingit a proper shapeto produce an apparent increase in the brightness or amagnification of the luminous indicating col-' umn, thereby improvingthe indication.

Since the electrodes are in the structure ac cording to the inventionoutside of the observation field, they may be formed and disposed so asto produce particularly favorable electrical and electron-opticalefiects. For example, it is in accordance with another object possible,to provide between the cathode and the support for the fluorescentsubstance a control electrode which is made in the shape of a shutterforming a wedgeshaped' cutout. "The size of such shutter may be sodimensioned that it 'doesnotad versally afiect the observation of'theindication. The invention also permits auxiliary utilization of thespace around the cathode (which is outside of the field of observation),for accommodating amplifier means and the total cathode'length may thusbe utilized as the electron source for such amplifier means. Theamplifier means may be preferably arranged upon the side of the cathodewhich is opposite to the electron stream. The discharge device may be inthe form of a fouror five pole tube and the amplifier means may bearranged for the implification of the high frequency or may be employedas a low frequency starter stage. The control electrode of theindicating system may be soconstructed and disposed that it controls theentire emission of the oath-- ode in a boosting sense.

The invention will now be described. more in detail with reference tothe accompanying drawings, wherein Fig. 1 illustrates in schematicperspective and exploded view the principal electrode members of anelectron discharge device embodying features of the invention;

Fig. 2 indicates in like schematic manneranother embodiment indiagrammatic sectional view;

Fig. 3 illustrates, in cross-section, a heartshaped form of thetransparent support of Fig. 1; and

Fig. 4 illustrates, in cross-section, a flat elongated striplike formofthetransparent support of'Figl.

The cathode in Fig. 1 is indicated by numeral I. It is a tubular cathodecarrying on the outside an emission layer and comprising in usual mannerinterior heating means 2. The shutter 3 has a wedgelike or V-shapedcutout and serves as a control electrode. The fluorescent substance 6 iscarried in a longitudinal groove 8 of the support 1, which may be aglass rod or the like. There are two anode members 4 and 5 which aremade of suitable sheet material and disposed so as to form a gaptherebetween, as shown. The support I is disposed so that the groove 8carrying the fluorescent substance faces the cathode through the gapformed by the anode members 4 and 5.

The glass support 1 may be ground longitudinally so as to form a planesurfacev (instead of the groove 8 shown) for receiving the fluorescentsubstance. The glass rod may also be cross-sec tionally heart shaped, asshown in Fig. 3 or may have another suitable cross-sectionalconfiguration such as shown in Fig. 4 so as to provide for desiredoptical effects, e. g., magnification of the luminous. column formed bythe fluorescent. substance or increase of the brightness thereof, asmentioned before.

In the embodiment shown inF'ig. 2, numeral 9 indicates the cathode whichmay be of cylindrical shape. A strip or band shaped. cathode ora-cathodeof different suitable form may of course be provided asdesired- A support it is provided which carries the fluorescentsubstance and a control electrode I l is disposed between the support Itand the cathode. The electrode H may be made in the shape of a shutterhaving a wedgelike opening, as described in connection with theelectrode 3 of Fig. 1. 7

The cathode 9 may be used thruout its length, in asuitable circuit, as apart of an amplifier tube system. The electrodes surround the cathode 9semi. spherically as shown. The individual electrodes are indicatedschematically. Numeral l2 represents the anode, 6.3 a brake grid, M ascreen gridandl5. designates a control grid. The structure may thereforeform a pentode for highand intermediate frequency amplification. Ifdesired, the. pentode may also be utilized as a low frequencyamplification tube.

Changes may be made withinthe scope and spirit of the appended claims.

We claim:

1. In an electron discharge device having a cathode, an anode and. acontrol electrode, a

fluorescent electrode comprising an elongated support made of glass orthe like transparent material, a strip of a fluorescent substancecarried by said elongated transparent support only on the side thereofwhich faces the cathode, said fluorescent substance being. renderedluminous to provide a bright indicating column of variable lengthresponsive to varying voltages applied to said discharge device, saidtransparent support permitting unobstructed observation of the entireluminous column throughout its entire area from a. direction inback ofthe strip of fluorescent substance carried thereby. I

2. .The structure defined in claim 1, together with a substantiallytransparentlayer of a. conductive material carried by said transparent.support underneath said fluorescent substance.

3. The structure defined in claim 1, wherein said transparent support isof cylindrical crosssection.

4.. The structure defined in claim 1, wherein said transparent supportis of heart-shaped crosssection.

5. The structure defined in claim 1, wherein said transparent support isa flat elongated striplike member.

6. The structure defined in claim 1, wherein said control electrode is aflat sheet member in which is formed a wedge-shaped cutout, said memberbeing disposed between said cathode and said transparent support forsaid fluorescent electrode to control the emission of said cathode. '7.An electron discharge device comprising a cylindrical cathode, a pair ofanode members, said anode members being disposed to form an elongatedgap therebet'ween, a control electrode having a wedge-shaped cutoutformed therein, said control electrode being disposed between saidcathode and said anode members, a fluorescent electrode disposed in backof the gap between said anode members, said fluorescent electrodecomprising an elongated support made of glass or the like transparentmaterial, a narrow strip of a fluorescent substance carried by. saidtransparent support only on the side thereof which faces said cathodethrough said gap between said anode members, said fluorescent substancebeing rendered luminous to form a bright indicating column of variablelength responsive to varying voltages applied to said discharge device,said transparent support permitting unobstructed observation of theentire luminous indicating "column throughout its entire area from adirection in back of the strip of the fluorescent substance carriedthereby.

8. An electron discharge device comprising a cylindrical cathode, asemi-spherical anode with its concave side radially spaced from saidcath' ode, a plurality of semi-spherical grid electrodes disposedbetween said cathode and said anode, a flat control electrode in whichis formed a wedge.- shaped cutout, said control electrode being disposedadjacent said cathode with one side there of facing said cathode and theinside of the semispheri'cal electrodes in back of said cathode, afluorescent electrode disposed adjacent to said control electrode on theother side thereof, said fluorescent electrode comprising an elongatedsupport made of glass or the like transparent material, a strip of afluorescent substance car: ried by said transparent support only on theside thereof which faces said control electrode, said fluorescentsubstance being rendered luminous to form a bright indicating column ofvariable length responsive to varying voltages applied to said dischargedevice, said transparent support permitting unobstructed observation of.the en.- tire luminous indicating column throughoutv its entire areafrom a direction in back of the strip of the fluorescent substancecarried. thereby.

WERNER JACOBI. HERMANN' HINDERER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,994,725 Orth Mar. 19, 19352,130,162 Thompson Sept. 13, 1938 2,175,700 Roberts 0013510, 19392,223,285 Heins NOV. 26, 1940 2,243,034 Heins lVIay 20, 1941 2,273,800Jensen d Feb. 17, 1942 2,394,857 Hultquist Feb. 12,1946

